What is Outdoor Fiber Optic Cable?


In wiring projects, you might have heard of both outdoor and indoor fiber optic cables. However, if you’re not familiar with the field, you might not know what an outdoor fiber optic cable is. Let’s take a closer look at what it is.

1. What is an Outdoor Fiber Optic Cable?
In simple terms, outdoor fiber optic cable is a type of optical cable that is specifically designed for outdoor use. It is tough, can withstand wind and sun exposure, and has a robust outer jacket to protect the cable. Additionally, it has mechanical and environmental characteristics like pressure resistance, corrosion resistance, and tensile strength.

An outdoor fiber cable is a communication line that transmits optical signals. The cable core consists of a certain number of optical fibers arranged in a specific manner and is surrounded by a sheath. The bare fiber is prone to breakage, so the fiber optic cable jacket provides protection for the shielding and conductors inside the cable. The most common material used for the jacket of outside plant fiber optic cables is PE.

Outdoor fiber cables are used for outdoor purposes, whereas indoor fiber optic cables are used indoors. To learn more about the differences between indoor and outdoor fiber optic cables, you can follow here.

2. Types of Outdoor Fiber Optic Cable
Outdoor optical cable design is complex due to limitations in building environments and installation conditions. There are different types of outdoor fiber optic cables based on structure, location of use, scope of use, and number of fiber cores.

2.1 Outdoor Cables by Structure


  • Central Loose Tube Outdoor Cables: The optical cable has a loose tube in the center, surrounded by a strengthening member. The number of optical cables is typically fewer than 12 cores.
  • Stranded Outdoor Cables: The center of the optical cable contains a strengthening member, with 5 to 12 loose tubes twisted around it in an SZ twisting pattern. This results in an optical cable with a higher number of cores by combining loose tubes. The loose tubes are usually color-coded with red and green for easy differentiation.
  • Slotted Core Outdoor Cables: The optical cable has a reinforcing member in the center, made of a plastic skeleton groove. The optical fiber or fiber ribbon is housed in the skeleton groove and is protected from compression.
  • Figure 8 Self-Supporting Outdoor Cables: This type of optical cable can have either a central tube or a layer-stranded structure. The optical cable has a sling outside, usually made of seven 1.0mm diameter steel wires or a 2.5mm galvanized steel wire.

2.2 Outdoor Cables by Location
There are three types of outdoor fiber optic cables based on location: outdoor trunk cables, outdoor distribution cables, and outdoor relay cables. Outdoor trunk cables connect the inside and outside of buildings, while outdoor distribution and relay cables transmit information to specific locations.

2.3 Outdoor Fiber Cable by the Scope of Use
Outdoor optical cables are mostly used in building complex systems and can be used in various environments such as direct burial, pipelines, overhead, and underwater. The main features are as follows:

  • Aerial optical cable: PE sheath provides good UV protection, and AT sheath withstands strong electrical corrosion. Non-self-supporting overhead cables have corrugated steel belt bearing capacity, while self-supporting overhead cables have high-strength steel strand bearing capacity.
  • Pipeline optical cable: aluminum tape is ideal for pipelines, offering a compact structure, excellent waterproofing, and good mechanical and temperature performance.
  • Direct Buried Optical Cable: This type must have double sheathing, with at least one layer of armor.
  • Air Blown Micro Cable: This cable has a specially designed compact structure to prevent loose tube shrinkage.
  • Underwater Optical Cable: The casing material is hydrolysis-resistant and strong. The cable paste provides protection for the optical fiber.


2.4 Outdoor Fiber Optic Cable by Fiber Core Number
Outdoor fiber optic cables are classified into two types based on the transmission mode of optical fibers: single-mode and multi-mode.

Single-mode Fiber: This type of fiber transmits only one propagation mode in the working wavelength. It is widely used in cable television and optical communication due to its smaller distance loss compared to multi-mode fiber. The core of single-mode fiber is thin, allowing light to be launched directly to the center.

Multi-mode Fiber: This type of fiber has multiple modes of propagation and a core diameter of 50um. The transmission mode can reach several hundred, resulting in a bandwidth dominated by modal dispersion. The effective transmission distance is around 5 miles, although it can be affected by the type and quality of the transmitter/receiver device. The bandwidth of multi-mode fiber is around 4000Mb/s.

The choice between single-mode and multi-mode fiber usually depends on the distance. If the distance is short, multi-mode fiber is preferred because the required transmitters/receivers are cheaper. For longer distances and large bandwidth data signals, single-mode fiber is a better option. Outdoor optical cables typically use single-mode fiber.

2.5 Outdoor Fiber Optic Cable by Materials
Outdoor fiber optic cables have a higher tensile strength, thicker protective layers, and are often armored with metal. They are mainly used for interconnecting buildings and remote networks.

The materials used in outdoor optical cables include different fillers, strengthening members, and sheaths. For example, when burying the cable directly, an armored optical cable should be used, while an optical cable with a black plastic outer sheath with two or more reinforcing ribs can be used when overhead.

Since outdoor optical cables are used outdoors, they must have a waterproof function. The outer sheath is usually made of PE material.

3. Application of Outdoor Cables

  • Long-distance and inter-office communication transmission
  • Essential for optical communication in the core network and metropolitan area network
  • Used for outdoor feeder and wiring in the access network

4. Characteristics of Outdoor Fiber Optic Cable

  • Water blocking tape is applied to prevent water seepage along the cable
  • Strong tensile strength and thick protective layer provide resistance against stretching, abrasion and impact
  • Offers fast transmission speed over long distances with high confidentiality, anti-electromagnetic interference, good insulation, chemical stability, long lifespan and low signal loss
  • PE sheath provides excellent protection against ultraviolet radiation

5. Summary


The above is an introduction to outdoor optical cables. Bonelinks is a leading supplier of outdoor fiber optic cable, offering a wide range of options to meet your specific needs. Our outdoor-rated fiber optic cables are not only stronger and more durable than copper cables, but also UV resistant and/or flame retardant. With larger, rugged cable constructions, we ensure that our fiber optic cables can withstand harsh outdoor environments and eliminate any concerns regarding UV and durability. If you require our services, please don’t hesitate to reach out to us.

Echo Huang

Echo Huang is an expert wordsmith and marketing professional at Bonelinks with more than 8 years of experience in high technology businesses – fiber optics, IoT, and telecommunication. She is very glad to share industry knowledge and communicate with others.

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